1. Field of the Disclosure
The invention relates to cranes, and more particularly to a carrier for cranes to transport and carry crane mats and pads.
2. Background Art
Cranes are useful at construction and lifting sites for constructing buildings, bridges and other structures, as well as for lifting loads. Cranes are machines, generally equipped with a tower, derrick, hoist, wire ropes, chains, cables, pulleys and/or sheaves, that can be used to lift and lower materials (loads) and to move them horizontally. Cranes are mainly used for lifting heavy loads and transporting them to other places. Cranes are also used in the transport industry, such as on ships and loading docks for the loading and unloading of crates, supplies, products, and freight. Cranes are farther used in the petroleum industry and manufacturing industry for the assembling of drilling rigs and heavy equipment.
The basic crane can have a steel truss or telescopic boom on a mobile platform mounted on a stationary or mobile chassis on wheels or crawler threads. The boom can be hinged at the bottom and can either be raised or lowered by cables and/or hydraulic cylinders. Other types of crane include: a rough terrain (RT) crane, telescopic crane, tower crane, truck mounted crane, loader crane, overhead crane, wheel mounted crane, wheel-mounted crane with latticework boom, commercial truck-mounted crane with hydraulic boom, commercial truck-mounted crane with articulated boom, commercial truck-mounted crane with trolley boom, crawler mounted latticework boom crane, overhead track-mounted crane, monorail crane, underhung crane, straddle crane, hammerhead tower crane, all-terrain crane, dragline crane, gantry crane, tower crane, industrial crane, truck crane, crawler crane, carry deck crane, jib crane, aircraft carrier crane, and stiff-leg derrick crane, shipyard crane, loading dock crane, and outrigger crane.
Cranes for construction are often placed at a construction site, lifting site, or other job site for 9 months or more and can be stationary and fixed to the ground, or can be mobile and supported on wheels or crawler threads. Cranes can be controlled by a crane operator in a cab on the crane or remotely by radio frequency (RF) push button controls. Stationary cranes lack wheels or self-locomotion abilities, and they need to be physically transported.
Cranes are often temporarily located at construction sites, lifting sites, or other job sites. After performing lifting operations and other tasks for a limited time, a crane can be transported to another site for the next set of operations. In this way, crane operations can support many construction projects with a limited number of cranes. For these and other reasons, the setup and tear down operations for a crane can occur quite frequently.
A number of support or accessory devices are used in the setup of the crane. Some of these accessories are involved in blocking the wheels, while others are used to stabilize the crane. These accessories are generally directed to supporting the cranes in a safe, convenient, and effective manner.
Each setup operation generally involves movement of the crane to a desired location and then stabilization using outriggers, crane mats, and/or pads. Because the tires or crawler threads on a crane often do not provide the stability needed to keep the crane balanced, the use of outriggers, crane mats and/or pads is often helpful to keep the crane upright and from leaning too much to one side or the other. Outriggers can be attached to the crane and can be comprised of a beam, which is the leg of the outrigger. Outriggers can provide crane stability when positioned on crane mats or pads which can distribute the applied loads to the ground. Once the outriggers are extended at a desired distance from the crane, crane mats or pads can be positioned below the outriggers, wheels, and/or crawler threads to help level and stabilize the crane.
Since it is important that cranes be stable during the lifting operation so the cranes do not accidently overturn, various accessories such as crane mats and pads can be used to provide a load-distributing, stable or otherwise robust foundation, base, or layer from which cranes operate.
There are many types of crane mats and pads which can be used for a variety of purposes. Some examples include: steel, wood, plastic, and hardened rubber crane mats and pads which can be round, rectangular, and other shapes and can have handles or no handles.
Crane mats and pads can be used to support outriggers, wheels, and/or crawler threads of the crane. When construction occurs in uneven terrain, soft ground or on surfaces that are difficult for cranes to operate, crane mats and pads are used so that the crane has a solid foundation for support and stability. Construction sites, lifting sites, or other job sites can present a variety of ground conditions including wet or dry soil, mud, gravel, pavement, etc. Due to the heavy weight of the crane and loads carried by the crane, the crane mats and pads can help prevent shifting, tilting or sinking of the crane on the ground. Crane mats and pads can allow cranes to be used, transported, and moved over uneven surfaces, inhospitable landscapes, and other ground conditions.
Crane mats and pads can also be used with cranes that do not use outriggers. The crane mats and pads can be positioned underneath wheels, crawler threads, or other supports associated with the crane.
At some lifting sites, construction sites, or other job sites, the use of mats and/or pads is mandatory, thereby requiring the crane operators to haul the crane mats and pads with or to the crane. A large number of crane mats and pads are often transported with the crane between job sites. At a minimum, at least one crane mat or pad is generally used with each one of the outrigger feet, wheels, and/or crawler threads. Moreover, different types and sizes of crane mats and pads can be used to accommodate different ground surfaces and other site conditions. For these reasons, numerous crane mats and/or pads are usually transported with a crane.
Crane mats and pads are put under enormous loads, forces, and physical stress. Crane mats and pads bear the weight of massive cranes and loads. Since cranes are often placed over uneven ground surfaces, the weight and forces exerted on the crane mats and pads are not often evenly exerted or distributed.
The logistics of moving crane mats and pads are often complex and difficult. In the past, crane mats and/or pads have been transported and hauled on the deck of cranes or on trains, semi-trailer trucks, or other vehicles. Once at the lifting site, construction site, or other job site, the crane can be set up for lifting operations. This is burdensome and costly because it can require the use of additional vehicles and counter-balancing equipment. The set up operation involves having ready access to the crane mats and pads and placement of the crane mats and/or pads under the wheels, crawler threads, and/or outriggers.
There are many challenges with the use of crane mats and pads, such as the transportation, accessibility and storage of the crane mats and pads for use with the crane. Cranes have very little accessible space for carrying and transporting crane mats and pads. The placement of crane mats and pads on the deck of the crane itself can cause significant wear, tear, scratching, and damage to the deck of the crane surfaces and can sometimes interfere with operating structures such as rotation of the crane body relative to the platform. The crane mats and pads can also cause extensive damage when the crane mats and pads are dirty, or abrasive materials become lodged in the surface of the mats. For example, if the crane mats and pads are used on gravel or rocks, gravel, pebbles, and other grit can become embedded in the surface of the crane mats and pads and cause undesirable scratching and chipping of the deck of the crane when the crane mats and pads are placed on the deck. Moisture on the crane mats and pads can also cause rust and corrosion.
The weight of each crane mat and pad can be significant, typically at least 50-60 lbs., with some weighing as much as 300 lbs. Furthermore, crane mats and pads can be expensive and are expected to be used many times. As a result, the handling and transport of the crane mats and pads often is complicated, difficult and inconvenient. Cranes can be damaged, and crane crew members can become injured from complications arising from the handling, storage, and transportation of crane mats, pads, and other accessories.
Additional challenges result from the height of the deck of the crane. The crane operator and crew members often place, remove, or reach for the crane mats and pads over their heads onto the deck of the crane. Due to the substantial height of the deck of the crane above the ground, it is very difficult for the crane operator and crew to easily and comfortably place and remove the crane mats and pads on the deck of the crane. Insertion and removal of crane mats and pads from the crane deck can cause back injuries, muscle sprains, and other problems for the crane operator and crew. Furthermore, damage to the crane and its components, e.g. a pinched hose, can also result if the crane mats and pads are accidentally dropped onto other parts of the crane.
It is, therefore, desirable to provide an improved crane mat carrier, which overcomes most, if not all of the preceding problems.